Human brain mapped in unprecedented detail

Researchers have divided the brain into discrete areas based on structure and function.

Think of a spinning globe and the patchwork of countries it depicts: such maps help us to understand where we are, and that nations differ from one another. Now, neuroscientists have charted an equivalent map of the brain’s outermost layer — the cerebral cortex — subdividing each hemisphere’s mountain- and valley-like folds into 180 separate parcels.

Ninety-seven of these areas have never previously been described, despite showing clear differences in structure, function and connectivity from their neighbours. The new brain map is published today in Nature1.

Each discrete area on the map contains cells with similar structure, function and connectivity. But these areas differ from each other, just as different countries have well-defined borders and unique cultures, says David Van Essen, a neuroscientist at Washington University Medical School in St Louis, Missouri, who supervised the study.

Yet until now, most such maps have been based on a single type of measurement. That can provide an incomplete or even misleading view of the brain’s inner workings, says Thomas Yeo, a computational neuroscientist at the National University of Singapore. The new map is based on multiple MRI measurements, which Yeo says “greatly increases confidence that they are producing the best in vivo estimates of cortical areas”.